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3.3 Volcanic Landforms


Vocabulary


shield volcano- when lava flows, it make a sloping mountain
cinder cone- a cinder cone is a steep, cone-shaped hill or it could be a mountain
Composite Volcanoes- tall mountains shaped like cones and are covered with layers of lava alternate with layers of ashes
caldera- a huge hole left by a volcanic mountain that collapsed
volcanic neck- when magma hardens in the volcano's pipe
dike- when the magma forces itself across the rocks layer it hardens
sill- when the magma goes between layers of hard rock
batholith- a mass of rock that forms when a large body of magma in the crust cools

Outline


Landforms From Lava and Ash

  • shield volcanoes
    • in some places in the Earth's surface, thin layers of lava pour out of a vent and harden on top of previous layers
    • the lava gradually builds a wide, gently sloped mountain
  • cinder cone volcanoes
    • a steep, cone shaped hill or mountain
    • if a volcano's lava is thick and stiff, it may produce ash, cinders, and bombs
      • these materials pile up around the vent in a steep, cone-shaped pile
  • composite volcanoes
    • tall, cone-shaped mountains which layers of lava alternate with layers of ash
  • lava plateaus
    • some eruptions of lava form high, level areas called plateaus
    • lava is thin and runny, so it can travel far before cooling
      • after millions of years, the layers of lava can form high plateaus
  • calderas
    • enormous eruptions could empty the volcano
      • mountain becomes a hollow shell
        • mountain caves in and is filled with remains of the volcano, as well as some lava and ash

Soils from Lava and Ash

  • the soils made from the lava is extremely fertile, so people settle near volcanoes

Landforms from Magma

  • volcanic necks, dikes, and sills
    • a volcanic neck forms when magma hardens in a volcano's pipe
    • magma that forces itself across rock layers hardens into a dike
    • when magma squeezes between layers of rock, it forms a sill
  • batholiths
    • a batholith is a mass of rock formed when a large body of magma cools inside the crust
  • dome mountains
    • forms when rising magma is blocked by horizontal layers of rock
    • the magma forces the layers of rock to bend upward into a dome shape